Chills after eating can be due to various reasons. Sometimes, more likely to happen if someone has lost a lot of body weight.
It can be related to thyroid or kidney problems or changes in blood pressure. Or even changes in blood sugar levels. It may help to eat small meals or snacks slowly, avoid very cold foods such as ice cream and to put on a few layers of clothing on after eating.
It would make sense to let the doctor know that this is happening, and see what they say about it.
